1. Field of the Invention
The present invention relates to an electrical connector for connecting together two boards.
2. Description of the Related Art
A board-to-board interconnect system for connecting together mother and daughter boards is known. In this system, two circuits of both surfaces of the mother board and two circuits of both surfaces of the daughter board are simultaneously connected by a pair of connectors.
The system comprises a plug housing attached to the edge portion of the daughter board and a receptacle housing attached to the edge portion of the mother board.
The plug housing supports two plug terminal rows corresponding to the two circuits of both the surfaces of the daughter board. The receptacle housing supports two receptacle terminal rows corresponding to the two circuits of both the surfaces of the mother boards.
The two plug terminal rows on the plug housing are molded in a blade-like fashion and arranged in a parallel array in close proximity in an electrically insulated fashion.
The two receptacle terminal rows of the receptacle housing are electrically insulated from each other in a spaced-apart relation. The two blade-like plug terminal rows can be matingly connected between the two receptacle terminal rows. Further, the respective receptacle terminal rows are of a cantilever beam type and can be brought in elastic contact with the blade-like terminal rows.
Further, the plug housing has a pair of guide pins projected from an inside at its middle and a pair of guide holes corresponding to associated guide pins of the plug housing are provided in an inside at a middle of the receptacle housing.
With these two housings attached to the edges of the corresponding boards, the two blade-like plug terminal rows are matingly connected to the two receptacle terminal rows. By so doing, the circuit on one surface of the mother board is electrically connected to the circuit on one surface of the daughter board and, at the same time, the circuit on the other surface of the mother board is electrically connected to the other surface of the daughter board.
Further, the two housings are mechanically connected together under a frictional force between the plug terminal row and the receptacle terminal row and an engaging force between the guide pin and the guide hole.
Only the frictional force and engaging force as set out about are not enough great to connect together these two housings, so that the housings are liable to be displaced away from each other and dropped.
The two terminal rows in the respective housing are provided in an entirely symmetrical relation. Therefore, even if one of these boards is inverted relative to the other board and hence their polarities are inverted for signal transfer to and from the boards, the two plug terminal rows can be matingly connected to the receptacle terminal rows, thus involving a risk that the mother board and daughter board will be connected together with their polarities wrongly set.
In order to prevent a connection error, it is conceivable that two terminal rows are non-symmetrically configured relative to the polarities of the boards so that the plug connection terminal rows can be connected to the receptacle connection terminal rows.
In this case, however, the configuration of the terminal is complicated so that the respective terminals are difficult to manufacture and mold.
It is also conceivable that pins are added to a connector device for correct polarity designation, but that the number of pins involved is increased.